Sensitivity and specificity of the FAMACHA© system in Suffolk sheep and crossbred Boer goats

Abstract

Sheep and goats are the species of farm animal with the highest growth rate in Paraná State. The main problems facing Paraná State flocks are gastrointestinal parasites and anthelmintic resistance. One of the newest resources used to slow down the development of anthelmintic resistance is the FAMACHA © system, a selective method useful for controlling gastrointestinal verminosis in small ruminants. The purpose of the present research was to evaluate the sensitivity and specificity of the FAMACHA © system in sheep and goats and to compare the results for both species. The conjunctivae of 83 Suffolk ewes and 60 adult cross-bred Boer does were evaluated by the same trained person using the FAMACHA © system. The packed cell value (PCV) served as the gold standard for clinical FAMACHA © evaluation. To calculate the sensitivity and specificity of the FAMACHA © system, different criteria were adopted in turn: animals classified as FAMACHA © (F © ) 4 and 5, or 3, 4 and 5, were consid-ered to be anemic (positive test), and animals classified as F © 1, 2 and 3, or 1 and 2 were considered to be non-anemic (negative test). Three standard values of PCV, namely ≤19%, ≤18% or ≤15%, were used to confirm anemia. At all cut-off levels, the sensitivity increased if F © 3 animals were included as being anemic. However, changes in levels of sensitivity were associated with reciprocal changes in specificity. The sensitivity was higher for sheep than for goats, excepting when the criteria included PCV ≤ 18 and F © 3, F © 4 and F © 5 were considered positive. In contrast, the specificity was always lower in sheep for any criteria adopted. Other than in goats, using the ≤15 cut-off level for sheep, it is possible to opt not to drench the animals that were shown to be F © 3 because the sensitivity is still high, indicating that few animals that should have been drenched were overlooked. In goats, in contrast, the low sensitivity at all cut-off levels made it too risky to leave F © 3 animals undrenched. Even though the number of correct treatments for goats was always higher than that for sheep, the opposite was true for the kappa index for all the criteria tested. Therefore, the FAMACHA © system is suitable for the identification of anemic animals of both species. It is necessary that all small ruminants classified as FAMACHA © level 3 are also treated to increase the sensitivity of the method.

Resistance to gastrointestinal parasite infection in Djallonké sheep

“…A relatively strong relationship between FAMACHA scores and PCV has commonly been reported in sheep and goats (Kaplan et al, 2004;Burke et al, 2007;Sotomaior et al, 2012). However, in contrast with results from the current study, associations between FAMACHA scores and FEC were often (Kaplan et al, 2004), though not always (Burke et al, 2007), weaker than those between FAMACHA scores and PCV.…”

Toward laboratory blood test-comparable photometric assessments for anemia in veterinary hematology

“…1(a). The most commonly used method for conjunctival redness is the FAMACHA system, 4,[5][6][7] which allows simple clinical evaluation of anemia by use of an eye color chart. 8,9 As a qualitative assessment of anemia, FAMACHA has been successfully used for aiding anemia diagnosis for small ruminant management, particularly in sheep and goats.…”

Método FAMACHA para detectar anemia clínica causada por Haemonchus contortus em cordeiros lactentes e ovelhas em lactação

“…O resultado verdadeiro negativo foi considerado como um animal que não estava anêmico apresentando a conjuntiva vermelha ou rosa. A sensibilidade, especificidade, o valor preditivo do resultado negativo e o valor preditivo do resultado positivo foram calculados de acordo com Vatta et al (2001), Thrusfield (2005) e Sotomaior et al (2012). A análise dos dados obtidos incluiu estatística descritiva (média e frequências) e análise de correlação (coeficiente de Pearson).…”

“…Desde que o método FAMACHA (FMC) foi desenvolvido para o controle seletivo de H. contortus em ovinos, sua eficácia foi testada e validada por vários pesquisadores em diferentes países (Van Wyk & Bath 2002, Kaplan et al 2004, Molento et al 2004, Depner et al 2007, Di Loria et al 2009, Sotomaior et al 2012. A adoção do método na seleção de animais que necessitam receber tratamento tem mostrado redução no número de doses e no custo com medicação antiparasitária (Bath & Van Wyk 2001, Molento et al 2004.…”